10.1071/BT18088 AC © CSIRO 2018 Supplementary Material ... · with a Panasonic Lumix DMC-FT5®...
Transcript of 10.1071/BT18088 AC © CSIRO 2018 Supplementary Material ... · with a Panasonic Lumix DMC-FT5®...
10.1071/BT18088_AC
© CSIRO 2018
Supplementary Material: Australian Journal of Botany, 2018, 66, 647–656.
Invasive alien palm Pinanga coronata threatens native tree ferns in an oceanic island
rainforest
Michael J. B. DyerA,B,I, Gunnar KeppelA,C,D, Marika TuiwawaE, Sainivalati VidoF and Hans Juergen
BoehmerG,H
ANatural and Built Environments Research Centre, School of Natural and Built Environments and
Future Industries Institute, University of South Australia, Mawson Lakes Campus, GPO Box 2471,
Adelaide, SA 5001, Australia.
BUnited Nations Development Program, MCO for Cook Islands, Niue, Tokelau and Samoa, Apia,
Samoa.
CFuture Industries Institute, University of South Australia, Mawson Lakes Campus, GPO Box 2471,
Adelaide, SA 5001, Australia.
DBiodiversity, Macroecology and Biogeography, Faculty of Forest Sciences, University of
Goettingen, Büsgenweg 1, 37077 Göttingen, Germany.
ESouth Pacific Regional Herbarium, Faculty of Science, Technology and Environment, University of
the South Pacific, Suva, Fiji.
FForestry Department, Ministry of Fisheries and Forests, Suva, Fiji.
GSchool of Geography, Earth Science and Environment, Faculty of Science, Technology and
Environment, University of the South Pacific, Suva, Fiji.
HInstitute for Applied Ecological Studies (IFANOS), Baerenschanzstrasse 73, Nuremberg, Germany.
ICorresponding author. Email: [email protected]
Supplementary Materials
Sampling design
Figure S1. The systematic grid sampling design applied in Colo-i-Suva Forest Park and Savura Forest Reserve
on Viti Levu, Fiji, to assess the abundance of Pinanga coronata and native tree ferns. Crosses indicate the
locations of known introduction sites of P. coronata.
S2 - Description of the response and explanatory variables
Table 1. The response variables measured in each 25 m2 plot and a brief description of the method used to
obtain their values.
Response variable Method description
Number of palm
clumps
The number of palm clumps.
Number of stems The number of stems in each clump. If a palm was mature but had not formed a clump,
it was considered to have only one stem.
Mean number of
stems
The sum of stems per plot was divided by the number of clumps.
Number of palm
seedlings
The number of seedlings (< 0.5 metres in height).
Palm cover (%) The crown area of each palm was estimated using a measuring tape. The total crown
area of palms in a plot was divided by the area of the plot to obtain an estimate of palm
cover.
Mean palm height
(metres)
The height of each palm was measured and the sum of each palm's height was divided
by the number of palm stems.
Max palm height
(metres)
The height of the tallest palm in the plot.
Juvenile tree fern Abundance of tree ferns between 0.1 - 1 metre in height.
Mature tree fern Abundance of tree ferns > 1 metre in height.
Tree fern saplings Abundance of tree ferns < 0.1 metre in height.
Tree fern cover (%) Calculated by measuring the frond area of each tree fern. The total frond area in a plot
was divided by plot's area to obtain an estimate of tree fern cover.
Tree fern volume Volume was estimated by multiplying the basal area of the caudex by its height
Maximum tree fern
height (metres)
Tallest tree fern in the plot.
Minimum tree fern
height (metres)
Shortest tree fern in the plot (excluding saplings).
Mean tree fern
height (metres)
The mean height of tree ferns in the plot (excluding saplings).
Table 2. The explanatory variables measured in each 25 m2 plot and the method description to obtain
their values.
Explanatory variable Method description
Habitat type Classified if the plot was in a mahogany plantation or lowland rainforest,
coded as 1 and 2.
Topography Classified as a ridge, valley or slope and coded as 1, 2 and 3,
respectively.
Elevation (metres) Height from mean sea level, measured on a Garmin Etrex 30®.
Slope (°) Inclination measured from the centre of the plot using a
LaserTechnology Inc True Pulse 360°B® rangefinder.
Canopy cover (%) Estimated crown area directly above the centre of the plot, calibrated
with a Panasonic Lumix DMC-FT5® digital camera.
Canopy height (metres) Measured using a LaserTechnology Inc True Pulse 360°B® rangefinder
with the standard height operating procedure.
Percentage of exotic volume The percentage of exotic tree volume was calculated by dividing exotic
tree volume by the total tree volume (native and exotic) in the plot.
Distance to nearest watercourse
(metres)
Measured remotely using a Viti Levu watercourse layer.
Distance to nearest forest edge
(metres)
Measured remotely using a Viti Levu roads layer and the boundary of
Colo-i-Suva Forest Park and Savura Forest Reserve.
Distance to the nearest introduction
site (metres)
Measured remotely from the nearest introduction site.
S3 - Descriptive statistics
Table 3. Descriptive statistics (mean, standard deviation and range) of the response and explanatory
variables in 90 lowland rainforest and mahogany plantation plots and the results of a Mann-Whitney U
test between these two habitats for each variable.
P-values were obtained at a 95% confidence interval (p <0.05).
Variable Lowland rainforest (n = 57) Mahogany plantation (n =33)
Mean ± Sd, range Mean ± Sd, range Mann-Whitney U value,
p-value:
Palm
clumps
2.51 ± 7.32,
0.00 - 43.00
5.06 ± 7.04,
0.00 - 32.00
W = 1302,
p <0.001
Palm stems 5.59 ± 14.97,
0.00 - 69.00
13.55 ± 24.52,
0.00 - 96.00
W = 1298,
p <0.001
Mean stems
per clump
1.45 ± 7.24,
0.00 - 9.75
1.33 ± 2.12,
0.00 - 9.40
W = 1292,
p <0.001
Palm
seedlings
23.89 ± 72.96,
0.00 - 389.00
62.42 ± 120.53,
0.00 - 613.00
W = 1292,
p = 0.001
Palm cover 14.14 ± 33.01,
0.00 - 100.00
40.00 ± 44.02,
0.00 - 100.00
W = 1321,
p <0.001
Tree fern
saplings
3.68 ± 3.62,
0.00 - 13.00
2.36 ± 4.09,
0.00 - 16.00
W = 671
p = 0.019
Juvenile
tree ferns
1.33 ± 1.73,
0.00 - 9.00
1.18 ± 2.39,
0.00 - 11.00
W = 779,
p = 0.14
Mature tree
ferns
2.43 ± 2.21,
0.00 - 9.00
1.88 ± 2.15,
0.00 - 7.00
W = 761,
p = 0.13
Tree fern
cover (%)
36.32 ± 28.82,
0.00 - 90.00
26.67 ± 29.65,
0.00 - 100.00
W = 757,
p = 0.12
Min tree
fern height
0.47 ± 0.92,
0.00 - 8.00
0.22 ± 0.59,
0.00 - 3.00
W = 564,
p = 0.0012
Max tree
fern height
2.96 ± 2.06,
0.00 - 8.00
2.11 ± 1.93,
0.00 - 8.00
W = 693,
p = 0.038
Mean tree
fern height
1.96 ± 1.54, 1.49 ± 1.31, W = 798.7,
0.00 - 6.00 0.00 - 5.50 p = 0.23
Tree fern
volume
0.06 ± 0.24,
0.00 - 1.79
0.01 ± 0.02,
0.00 - 0.13
W = 735,
p = 0.085
Elevation 173.50 ± 40.14,
79.00 - 267.00
178.10 ± 28.35,
118.00 - 230.00
W = 1054,
p = 0.35
Slope 18.22 ± 13.36,
0.40 - 45.50
13.12 ±14.56,
0.00 - 55.00
W = 713,
p = 0.057
Canopy
cover
56.49 ± 19.41,
20.00 - 90.00
57.27 ± 22.54,
20.00 - 90.00
W = 987,
p = 0.70
Canopy
height
22.93 ± 5.60,
12.00 - 37.00
29.72 ± 4.39,
20.00 - 40.00
W = 713,
p <0.001
Percent
exotic
volume
12.42 ± 31.59,
0.00 - 100.00
67.94 ± 42.65,
0.00 - 100.00
W = 1523.5,
p <0.001
Distance to
watercourse
55.79 ± 57.02,
1.00 - 241.00
55.25 ± 57.72,
1.00 - 253.00
W = 931,
p = 0.94
Distance to
nearest
forest edge
136.60 ± 103.45,
5.00 - 432.00
101.20 ± 97.07,
2.00 - 419.00
W = 767,
p = 0.151
Distance to
nearest
introduction
1632.20 ± 498.58,
576.80 - 2536.80
1091.40 ± 713.21,
150.70 - 2818.10
W = 500,
p <0.001
S4 - Spearman correlation coefficients among explanatory variables
Table 4. Spearman correlation coefficients (ρ) for the explanatory variables measured in 90, 25 m2 plots surveyed in Colo-i-Suva Forest Park and Savura Forest
Reserve, on Viti Levu, Fiji.
P-values were obtained at a 95% confidence interval (p <0.05).
Elevation Slope Canopy height Canopy cover Distance to
nearest
watercourse
Distance to nearest
forest edge
Distance to nearest
introduction site
Elevation 1 ρ = -7.2 x 10-3,
p = 0.95
ρ = 0.12,
p = 0.28
ρ = -1.0 x 10-3,
p = 0.86
ρ = 0.27,
p <0.001
ρ = -2.6 x 10-2,
p = 0.82
ρ = -0.35,
p <0.001
Slope 1 ρ = -0.11,
p = 0.30
ρ = 0.14,
p = 0.15
ρ = 4.5 x 10-2,
p = 0.68
ρ = 0.13,
p = 0.24
ρ = 0.07,
p = 0.51
Canopy height 1 ρ = -4.9 x 10-2,
p = 0.64
ρ = 6.1 x 10-2,
p = 0.57
ρ = 4.4 x 10-2,
p = 0.68
ρ = -0.46,
p = <0.001
Canopy cover 1 ρ = 0.052,
p = 0.63
ρ = 6.4 x 10-2,
p = 0.55
ρ = 0.25,
p = 0.02
Distance to nearest
watercourse
1 ρ = -0.11,
p = 0.32
ρ = 5.9 x 10-2,
p = 0.58
Distance to nearest
forest edge
1 ρ = 1.8 x 10-2,
p = 0.87
Distance to nearest
introduction site
1
S5 - Species list of the trees present in the survey
Table 5. The tree species present with a DBH ≥ 0.1 metre in 90, 25 m2 plots surveyed in Colo-i-Suva
Forest Park and Savura Forest Reserve, on Viti Levu, Fiji.
Genus/Species Family Native/Exotic Count
Agathis macrophylla (Lind.) Mast. Araucariaceae Native 1
Albizia sp. Mimosaceae Exotic 2
Anacolosa lutea Gillesp. Olacaceae Native 1
Atuna racemosa Raf, Sylva Tellur Chrysobalanaceae Native 4
Barringtonia spp. Lecythidaceae Native 4
Calophyllum vitiense Turrill Clusiaceae Native 1
Cerbera sp. Apocynaceae Native 2
Crossostylis spp. Rhizophoraceae Native 18
Dacrydium nidulum de Laub. Podocarpaceae Native 1
Decaspermum vitiense (A. Gray)
Niedenzu
Myrtaceae Native 1
Dillenia biflora (A. Gray) Mertelli ex
Dur & Jacks.
Dilleniaceae Native 7
Dolicholobium sp. Rubiaceae Native 1
Dysoxylum richii (A. Gray) C. DC. Meliaceae Native 5
Endospermum macrophyllum (Muell.
Arg.) Pax & Hoffm.
Euphorbiaceae Native 1
Eucalyptus sp. Myrtaceae Exotic 2
Garcinia myrtifolia A.C. Sm. Clusiaceae Native 6
Garcinia pseudoguttifera Seem. Clusiaceae Native 2
Geniostoma sp. Loganiaceae Native 1
Gironniera celtidifolia Gaud. Cannabaceae Native 1
Gnetum gnemon L. Gnetaceae Native 7
Gonystylus punctatus A.C. Sm. Thymelaeceae Native 4
Gymnostoma vitiense L.A.S. Johnson. Casuarinaceae Native 7
Haplolobus floribundus (C.T. White)
Leenh.
Burseraceae Native 3
Kingiodendron sp. Caesalpiniaceae Native 1
Genus/Species Family Native/Exotic Count
Macaranga sp. Euphorbiaceae Native 1
Maesopsis eminii Engl. Rhamnaceae Exotic 2
Melicope sp. Rutaceae Native 1
Myristica spp. Myristicaceae Native 19
Neuburgia sp. Loganiaceae Native 1
Pagiantha thurstonii (Horne ex Baker)
A.C. Sm.
Apocynaceae Native 1
Pandanus spp. Pandanaceae Native 4
Parinari insularum A. Gray Chrysobalanaceae Native 1
Pinus radiata D. Don Pinaceae Exotic 2
Pinus sp. Pinaceae Exotic 2
Spathodea campanulata Beauv. Bignoniaceae Exotic 1
Swietenia macrophylla King. Meliaceae Exotic 43
Syzygium spp. Myrtaceae Native 5
Terminalia sp. Combretaceae Native 2
Unknown sp. Unknown Exotic 2
Unknown sp. 2 Unknown Native 1
Veitchia joannis Vietch and H.A.
Wendl
Arecaceae Native 1
Xylopia pacifica A.C. Sm. Annonaceae Native 7
Total 179
S6 - Summary of the Generalised linear mixed effect model
Table 6. Parameters for significant explanatory, fixed-effect variables retained in the best generalised
linear mixed effect model (GLMM) explaining the abundance of P. coronata seedlings in Colo-i-Suva
Forest Park and Savura Forest Reserve on Viti Levu, Fiji.
Habitat type was set as the random effect, but did not explain any variance. Distance = Distance to nearest
introduction site. Degrees of freedom = 85.
Table 7. Parameters for significant explanatory, fixed-effect variables retained in the best model for
significant response variables in the best generalised linear mixed effect models (GLMMs) explaining the
abundance for three different size classes of tree ferns (saplings, seedling, mature).
Habitat type was set as the random effect, but did not explain any variance. Degrees of freedom = 85; NS = not
significant.
Saplings Juveniles Mature
F-value p-value Coeff. F-value p-value Coeff. F-value p-value Coeff.
Palm cover -3.45 <0.001 -7.9 x 10-3 -3.43 <0.001 -5.7 x 10-3 -3.08 0.002 -5.5 x 10-3
Slope 5.82 0.0036 1.9 x 10-2 2.67 0.0075 1.2 x 10-4 NS NS NS
Intercept 5.83 <0.001 0.89 4.48 <0.001 0.49 13.20 0.0 1.07
F-value p-value Coeff.
Intercept 10.02 0.00 5.26
Distance –7.38 <0.001 –1.9 × 10-3
Canopy cover –2.29 0.024 –1.8 × 10-2